2121111216 has 180 divisors, whose sum is σ = 7311944952. Its totient is φ = 570350592.

The previous prime is 2121111193. The next prime is 2121111217. The reversal of 2121111216 is 6121111212.

It is a super-2 number, since 2×2121111216² = 8998225581281997312, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is not an unprimeable number, because it can be changed into a prime (2121111217) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 111111 + ... + 128793.

Almost surely, 2^2121111216 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2121111216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3655972476).

2121111216 is an abundant number, since it is smaller than the sum of its proper divisors (5190833736).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2121111216 is a wasteful number, since it uses less digits than its factorization.

2121111216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17728 (or 17712 counting only the distinct ones).

The product of its digits is 48, while the sum is 18.

The square root of 2121111216 is about 46055.5231866928. The cubic root of 2121111216 is about 1284.8560687049.

Adding to 2121111216 its reverse (6121111212), we get a palindrome (8242222428).

The spelling of 2121111216 in words is "two billion, one hundred twenty-one million, one hundred eleven thousand, two hundred sixteen".